Over the past few decades, the advances in farming technology and the increase in population have increased the demand for crops and livestock in the agricultural industry. This growth in agricultural production has increased contaminants polluting waterways and soil. The increase in contaminants has prompted increased efforts to reduce the number of pollutants in rivers to improve overall water quality. Contaminated water is a global challenge that has increased in both developed and developing countries.
It has undermined economic growth as well as the physical and environmental health of billions of people. Although global attention has focused primarily on water quantity, water-use efficiency and allocation issues, poor wastewater management has created serious water-quality problems in many parts of the world, worsening the water crisis.
Contaminated Water Sources
Agriculture in several parts of the world is highly efficient in producing and delivering high-quality products to consumers. However, when agricultural activities are not managed and well-monitored, certain practices can negatively affect water quality.
According to the U.S. Environmental Protection Agency (EPA), nonpoint source (NPS) pollution is pollution that comes from many diffuse sources, unlike point sources such as industrial and sewage treatment plants. Contaminated water runoff is created by rainfall or snowmelt moving over and through the ground. As the runoff moves, it picks up.
It carries away human-made and natural pollutants, finally depositing them into watersheds via lakes, rivers, wetlands, coastal waters, and even our underground drinking water sources.
In the National Water Quality Inventory report for 2002 presented to U.S. Congress, the states reported that agricultural nonpoint source (NPS) pollution is the leading cause of stream and river impairment. It is also the second leading cause of impairment in reservoirs, lakes, and ponds.
The agricultural activities leading to nonpoint source pollution include:
- Poorly managed animal feeding operations
- Ineffective application and poorly managed and of pesticides, irrigation water, and fertilizer
- Overworking the land like plowing too often
Effects of Contaminated Water
Agricultural water can become contaminated in several ways and potentially spread bacteria, parasites, and viruses to animals and crops.
Fresh vegetables and fruits come in contact with water during various stages of the production process. Contaminated water used during crop production, harvesting, and processing can lead to health issues.
Here is a list of the potential food production points where contaminated water sources can affect crop production:
- Chemical Application – Crops with contaminated water are used for pesticide or herbicide applications. Water used for mixing chemicals should not be contaminated water, and it should be of appropriate quality.
- Irrigation – Irrigating crops using contaminated water must be prevented, and you should use water of appropriate quality.
- Worker Hygiene – Lack of potable water for hand hygiene. There should be an established hygiene and handwashing policy for farm workers.
- Food Processing – You must wash crops with quality water, especially during the final wash process. Water should be of drinking water quality and should not be recycled.
People who consume fruit or vegetables exposed to contaminated water are at risk of developing a foodborne illness. Some bacteria spread through water include Salmonella spp., Giardia, E. coli, Shigella spp., Cryptosporidium, norovirus, Toxoplasma, and Hepatitis A.
Irrigation of foods imported from international locations can spread these and other microbes (Cyclospora) which are not usually found in developed countries. Small amounts of any of these microbes can cause foodborne illness. To keep microbes out of water sources, farmers must practice appropriate for their operation and ensure they use the best quality water. Water quality is also vital in providing post-harvest quality by decreasing decay.
Farmers must provide livestock with quality water which must be free of contamination. Contaminated water can contain disease-causing microorganisms, which can rapidly spread if animals drink from the same trough. If you the quality of the water provided to livestock, it is essential to test the water to ensure its safety.
Many chemicals and microorganisms can be potentially dangerous for livestock. Some chemicals include sulfates, nitrates, and chemicals found in pesticides like DDT, Chlordane, and Endrin. Certain organisms, like blue-green algae, Cryptosporidium, or Staphylococcus, can be toxic to animals.
They can cause symptoms like diarrhea, labored breathing, lack of coordination, or death. If all animals can then release millions of infectious microbes into the soil, that can further contaminate other water sources.
Contaminated Water and United Nations
Water quality in agriculture, or the water pollution from and to agriculture, is a focus area for the Food and Agriculture Organization of the United Nations (FAO), under which different global and national projects and programs are identified. FAO looks at agriculture as a cause and victim of water pollution. Based on that, it has defined water quality-related activities in two categories:
Agriculture as a water polluter as a cause
Agriculture accounts for 70% of total water consumption worldwide. It is the single-largest contributor of non-point-source pollution to groundwater and surface water. Agriculture intensification is often accompanied by increased salinity, soil erosion, sediment loads in water, and excessive use of fertilizers to increase productivity.
Pollution caused by agriculture can contaminate food, fodder, water, farms, the natural environment, and the atmosphere. Agricultural fertilizers can contaminate groundwater and surface water, such as organic livestock wastes, silage effluents, antibiotics, and processing wastes from plantation crops.
Pollution caused by large-scale industrial farming, including livestock and fisheries is categorized as point-source pollution, and pollution caused by small-scale family-sized farming is considered non-point-source pollution. Globally, countries work with other UN and non-UN organizations to monitor, control, and mitigate pollution loads from agricultural activities and the negative impacts of agricultural pollution on people’s health and the environment.
In tackling this challenge, FAO takes a multidimensional and nexus approach to ensure that all aspects are covered – socio-economic, health, environmental, and food safety.
Agriculture as a user of marginal quality water as a victim
Modern-day farmers are looking increasingly at non-conventional water sources of marginal quality, including wastewater, with the increasing demand for agricultural commodities. When conventional water resources are scarce or lacking, domestic and municipal wastewater offers an attractive option due to water its high nutrient content.
Contaminated water leads Algal Blooms, Dead Zones, and Acidification
High quantities of nutrients in the water from industrial crop fertilizers and animal waste cause excessive aquatic plant growth causing “hypoxia,” or water that is low in oxygen. Harmful algal blooms occur when marine algae multiply out of control. Some HABs produce biotoxins, which can kill fish and other aquatic life and cause human illnesses, while others use up the oxygen in the water, creating “dead zones” where marine creatures cannot live.
Nitrogen fertilizer applied in the farm fields of US Midwest eventually makes its way to the Gulf of Mexico. This, along with runoff from animal waste, is one of the leading causes of the so-called Gulf “Dead Zone,” an oxygen-deprived area of 8,000 square miles in size, in which no fish can survive.
In places like the Eastern Shore of Maryland, home to thousands of chicken broiler houses, rivers have phosphorous concentrations among the highest in the nation, linked to the estimated 228,000 tons of excess chicken waste spread in the state. Ammonia from agricultural runoff can also degrade ecosystems by acidifying waterways, affecting the ecology of streams and rivers.
Contaminated Water and Industrial Agriculture
Industrial agriculture is one of the leading causes of water contamination. About 46 percent of our streams and rivers are in poor biological condition. This effectively means that high levels of nutrients and algae are degrading water quality. Water contamination from industrial agriculture can have many adverse effects on both the environment and people.
Both nitrogen and phosphorus are components of synthetic fertilizers and byproducts of animal waste. High levels of nitrogen and phosphorus threaten waterways’ health and biological diversity. This can result in the loss of aquatic life and their habitats, shellfish contamination, and seasonal dead zones. Beaches may close due to algal blooms. Polluted water impacts nearby residents’ quality of life and incomes, posing a threat to public health. Excessive nutrient runoff in waterways can impact water supply and cause severe health problems. As a result, fishing activities may be severely limited.
Contaminated Water and Outbreak of Disease
Animal waste comprises a high level of disease-causing microorganisms or pathogens. Swine waste can contain more than 100 pathogens that cause human diseases. Therefore, when leakages occur on a factory farm, contaminated water can end up in groundwater and waterways. Pathogens can survive after being sprayed onto farm fields, leaching into groundwater, or transported to surface water due to runoff. Hence, people can become sick by ingesting water during recreational activities such as swimming or boating or by consuming contaminated drinking water.
The use of non-conventional sources of water, like wastewater, in agriculture is not safe. It can lead to the accumulation of microbiological and chemical pollutants in crops, livestock products, and soil and water resources. Consequently, this can lead to severe health implications among exposed food consumers and farm workers.
Alternatively, it may also make a situation worse due to antimicrobial resistance. However, wastewater can be a valuable water source and source of nutrients. Consequently, it can contribute to food security and livelihood improvement if it is adequately treated and safely applied.